1. Field of the Invention
The present invention relates to a magnetoresistance effect type head and a magnetic recording/reproducing apparatus and, more particularly, to a magnetoresistive head including a soft magnetic shield and a magnetic recording/reproducing apparatus having the same magnetoresistive head.
2. Description of the Related Art
Some of magnetoresistive heads for detecting variations in magnetic field by use of a magnetoresistance effect element, include soft magnetic shields. FIG. 9 schematically shows a construction of this type of magnetoresistive head. As shown in FIG. 9, this type of magnetoresistive head is structured such that a magnetoresistance effect element 21 and an element terminal 22 are sandwiched in between an upper shield 25 and a lower shield 26 through first and second gaps 23, 24, and the lower shield 26 is connected via a slider protective film 27 to a slider 28.
The magnetoresistance effect element 21 involves the use of a spin valve element or an anisotropic magnetoresistance effect element. The first and second gaps 23, 24 and the slider protective film 27 involve the use of films each composed of an insulating material (normally alumina (Al.sub.2 O.sub.3)). Further, the upper and lower shields 25, 26 involve the use of films each made of a magnetic material exhibiting a high magnetic permeability, (normally, NiFe) and what is used as the slider 28 is composed of AlTiC (Al.sub.2 O.sub.3.TiC).
As known well, the magnetoresistive head described above is, after being formed by a thin film process, supplied to a manual operation on a table. On this occasion, it might happen that static electricity on the order of 100V is produced in a human body, and is therefore applied between the slider 28 and a unit consisting of the magnetoresistance effect element 21 and the element terminal 22 (the unit is hereinafter referred to as "a converting element unit"), with the result that discharging takes place between the converting element unit and the lower shield 26. As a consequence, it happened that the head was damaged (a performance was deteriorated).
In order to obviate such a problem, according to Japanese Patent Laid-Open Publication No. 9-44820, there is proposed such a contrivance that a dielectric substance having a capacitance on the order of 50 pF is provided between the element terminal and the lower shield. A construction of the magnetoresistive head disclosed in the above Publication and procedures of manufacturing the same head, will hereinafter be described with reference to FIG. 10.
According to the technique disclosed in Japanese Patent Laid-Open Publication No. 9-44820, at first, as shown in FIG. 10(A), alumina is deposited on a slider substrate 28, thereby forming the slider protective film 27. Subsequently, as illustrated in FIG. 10(B), NiFe is deposited thereon, and the lower shield 26 is thus formed.
Thereafter, as shown in FIG. 10(C), alumina is deposited in the vicinity of an air bearing surface (on a lower side in FIG. 10(C)), thereby forming a insulating film 24.sub.1 constituting a part of the second gap 24. Further, as shown in FIG. 10D, a dielectric film 24.sub.2 constituting the second gap 24 in combination with the insulating film 24.sub.1. Thereafter, as shown in FIG. 10(E), the magnetoresistance effect element 21 is formed on the insulating film 24.sub.1.
After forming the magnetoresistance effect element 21, as illustrated in FIG. 10(F), the element terminal 22 for detecting a change in resistance thereof is formed. Next, as shown in FIGS. 10(G) and 10(H), the first gap 23 and the upper shield 25 are formed, thereby obtaining the magnetoresistive head.
In the magnetoresistive head manufactured in these procedures, the capacitance between the element terminal 22 and the lower shield 26 increases, and hence discharging is hard to occur between the magnetoresistance effect element 21 and the lower shield 26. In this magnetoresistive head, however, the second gap 24 must be formed by combining two kinds of films, and therefore the manufacturing process becomes complicated.